ECOLOGYECOLOGY
Ecology• Definition: the scientific study of
interactions among organisms and their environment
– Branch of biology that was developed from natural history
– Study reveals the relationships between living and non-living parts of the world
Biosphere• Definition: portion of Earth that
supports life
– Goes from the top of the atmosphere to the bottom of the ocean
– Supports a wide variety of organisms
Factors Involved• Abiotic: non-living part of an organisms
environment• Air, temperature, moisture, soil, light
• Biotic: all the living organisms that inhabit an environment
Levels of Ecology• Organism: living member of species
• Population: group of organisms of one species that interbreed and live in the same place at the same time
Levels of Ecology• Community: collection of interacting
populations
• Ecosystem: made up of interactions among populations in a community and the communities physical
surroundings
Example……In a desert
• Organism: coyote• Population: pack of coyotes• Community: pack of coyotes, hawks,
owls, snakes, scorpions, & reptiles• Ecosystem: populations of animals
listed above, cacti, shrubs, sand dunes, climate, rocks, temperature
In an ecosystem• Habitat: a place where an organism
lives out its life
• Niche: the role and position a species has in its environment
• How it eats?• How it survives?• How it reproduces?
Succession• Primary Succession: colonization of
new sites by communities of organisms
• Secondary Succession: sequence of community changes that take
place after its disrupted by natural disasters or human action
Relationships• Symbiosis: when species, alike or
different, live together
• Commensalism: one species benefits and the other is neither harmed or benefited
– Like when moss (or plants) grow on a tree
Relationships• Mutualism: both species benefit
– Acacia trees and ants, never found apart
• Parasitism: one species derives a benefit from the other– Fleas and ticks
Nutrition• Autotrophs: organisms that
manufacture their own nutrients using stored energy or energy from
the sun
• Heterotrophs: cannot make their own food, they feed on autotrophs or other heterotrophs
Types of Heterotrophs• Herbivores: feed on plants
– Rabbits, grasshoppers, squirrels, etc
• Carnivores: feed on other animals– Lions, snakes, wolves, etc
• Scavengers: feed on dead animals– Vultures
• Decomposers: break down and absorb nutrients from dead organisms– Fungi and algae
Energy Flow• Food Chain: simple model that shows
how matter and energy move through an ecosystem
Algae Fish Heron
• Trophic Level: each organisms in a food chain represents a feeding step
Algae Fish Heron1st step 2nd step 3rd step
Energy Flow
• Food web: expresses all the possible feeding relationships at each
trophic level in a community– Page 53
Communities• Limiting factors: factors that affect an
organisms ability to survive in its environment
– Food availability, predators, temperature
• Succession: changes over time, species and environment replacements
Biomes
• Definition: large group of ecosystems that share the same community
• Freshwater, marine, and terrestrial
Marine Biomes• Separated into two zones for easier study
– Aphotic: deeper water that never recieves sunlight
– Photic: portion of marine biome shallow enough for light to penetrate
• Tides cause water levels to change
Marine Biomes
• Hundreds of different types of organisms live in the oceans
– From marine plankton in shallow waters to the humpback whales in the deep sea the ocean is full of biodiversity
Freshwater Biomes• Home to different kinds of plants and
organisms– Tadpoles, turtles, insects, lilies, shrubs
• As depth increases, less light penetrates – no photosynthesis and no plants, decomposers at the bottom recycle nutrients
Terrestrial Biomes
• As you move north, south, east, and west around the world
temperature, precipitation, and surroundings change
Tundra• Temperature: long summer days and
short periods of winter
• Plant Life: shallow rooted grasses, small plants
• Soil: underneath soil is called permafrost
• Animals: mosquitoes, lemmings, weasels, foxes, owls, hawks, oxen, caribou, reindeer
Taiga• Temperature: long severe winters,
short summers
• Plant Life: large fir trees, hemlocks, and spruce trees
• Soil: peat swamp habitat
• Animals: lynx, snowshoe hares, caribou – like the tundra
Desert• Temperature: arid, dry, hot
• Plant Life: almost nonexistent, cacti
• Soil: dry, sand dunes
• Animals: coytoes, hawks, owls, snakes, scorpions, and reptiles
Grasslandoccupies more area than any other biome
• Temperature: dry
• Plant Life: grass roots, oats, rye, wheat
• Soil: humus content high, sod underneath
• Animals: bison, wolves, coyotes, rodents, birds, reptiles
Temperate Forest• Temperature: cool winters and
summers there is moderate rainfall
• Plant Life: hardwood trees
• Soil: top layer humus, clay below
• Animals: squirrels, mice, rabbits, deer, birds, bears
Tropical Rainforest• Temperature: warm temperature,
wet surroundings
• Plant Life: deciduous trees, forest plants, lush growth
• Soil: thick wet mat on surface
• Animals: amazing amount of biodiversity
Populations• Population Growth: increase in the
size of a population over time– Does not grow linear, J-shaped growth
• Exponential Growth: as the population gets larger it grows faster
Population Growth
0
200
400
600
Population Size
Time
Growth of Houseflies
Can a population of organisms grow
indefinitely?
NO
Populations (cont)
• Carrying capacity: the number of organisms of one species that
an environment can support
– Under: births exceed deaths– Over: deaths exceed births
Environmental Influences
• Density-dependent factors: disease, competition, parasite, and food
• Density-independent factors: (abiotic) temperature, storms, flood, drought, and habitat disruption
Demography
• Definition: the study of human population growth characteristics
– Study growth rate, age structure, and geographic distribution
Population Vocabulary
• Growth rate: the difference between the birthrate and the death rate
• Fertility rate: the number of offspring a female produces during her
reproductive years
– when high – population grows fast
Population Vocabulary
• Age structure: proportions of a population that are of different levels
– Depicted in graphs– Used to predict if a population is growing
rapidly, slowly, or not at all
Mobility• Immigration: movement of individuals
into a population
• Emigration: movement out of a population
Population Game
• We will simulate a population today. Each person will imitate a
particular trophic level.
• Make sure that you read your “survival cards” before playing. They will be necessary to help you stay alive.
Population Game
Food ChainLions (2 students)
Hyenas (6 students)
Wildebeests (10 students)
Grass (13 students)
Population Game Rules• Make sure that you get all your energy
tokens and water tickets.
• Be careful of how many energy tokens you lose catching prey.
• Upon catching prey – return to Miss Pfeiffer and cash in energy token.
Population Game Rules (2)
• NO TACKLING OR FIGHTING.
• Stay within the boundaries of the “ecosystem”.
• Be sure to follow directions as far as eating different trophic levels.
Biodiversity• Definition: variety of life in an area
– Islands tend to have higher biodiversity– Includes all forms of life, plant and
organism
Importance of Biodiversity
• Nature: life depends on life
– When organisms are removed it affects other organisms
– Must have sufficient numbers in trophic levels
Importance of Biodiversity• People: humans depend on organisms
for their needs
– Oxygen is supplied and CO2 is removed by plants
– Diet – beef, chicken, tuna, shrimp, pork, etc.
– Health – antibiotics supplied by plants
Threats to Biodiversity
• Habitat loss
• Habitat fragmentation
• Abiotic and Biotic Issues
• Habitat Degredation
• Water and land pollution
Conservation of Biodiversity
• Conservation Biology: field of biology that studies methods and
implements plans to protect biodiversity
– Relatively new field of biology– Legal protection for endangered species
implemented by government
Water Cycle
Water Cycle #2
Carbon Cycle
Nitrogen Cycle